Method of producing electrodes.



PATENTED SEPI',.26,1905.

No. 800,181. I

11. SPBGKETER.

v METHOD or rnonuome ELECTRODES.

APPLIGATION Hum r1212. 18,1903.

UNITED STATES PATENT OFFICE.

HEINRICH SPECKETER, OF GRIESHEIM-ON-THE-MAIN, GERMANY ASSIGNOR TO THE FIRM OF CHEMISCHE FABRIK GRIESHEIM ELECTRON, OF FRANKFORT-ON-THE-MAIN, GERMANY.

METHOD OF PRODUCING ELECTRODES.

Specification of Letters Patent.

Patented Sept. 26, 1905 Application filed February 18, 1903. Serial No. 143,998.

I a subject of the German Emperor, residing and having my post-olfice address at 1 Bahnstrasse, Griesheimon -th'e-Main, Germany, have invented certain new and useful Improvements in Methods of Producing Electrodes, of which the following is a specification. 1

This invention relates to a method of producing electrodes from ferric oxid for electrolytical purposes.

Electrodes made of. magnetic ferric oxid are already long known in the literature, although they are not in practical use. For instance, by the United States Patent No. 518,710 to H. Carmichael, April 24, 1894, a method has been disclosed in which the electrodes are,

made from native magnetite by cutting the latter up into pieces of the convenient shape. Pure magnetite, such as is required for the said purpose, is, however, so very rare as to rendenits employment impossible, the more so since the waste of this rare mineral resulting from the said method is excessively large. Moreover, it is very difficult to work this hard and brittle material. Blackman (see United States Patent No. 568,231, dated September 22, 1896, and German Patent No. 92,612, August 7, 1895,) has attempted to remedy this defect by suggesting that the native magnetite and other conductive magnetic iron-oxid combinations should bemelted with or without suitable flux and from the mass so formed electrodes of the desired shape and size should be cast. However, thereby only the difiiculty of mechanically working the magnetite is avoided, while the other defects remain. The starting-point of similar known methods is the employment of magnetite, the same as in the said United States patent, and although in the latter it is stated that in place of the magnetite other magnetic ferric oxids may be used, yet no such combinations are specified which may be found in the necessary quantity and purity for satisfactorily supplying the demand ofelectrodes of the described kind. Especially the black slag named in this patent is onlymet with as the waste of blast-furnaces and can only be extracted from these furnaces when the latter are being repaired. Not only is this black slag not to be found on the market at all, but

also it presents the other defects of the magnetic iron ore, it being impregnated with foreign matters to such an extent that no one can think of employing it for the mentioned purpose. Hitherto actually no useful electrodes of the described kind have ever been on the market, although this article is in great demand. The reason of this lies in'the fact that, as already said above, the magnetic iron ore of the purity as required for the above-mentioned purpose is found too rarely. In case ordinary magnetic iron ore, such as is found everywhere in great quantities, is employed for the production of electrodes the latter presents the following defects, which render them utterly unfit for the technical use: first, the conductivity is very bad, owing to the great impurity of the magnetite, so that the electrolytical baths require too excessive a tension of the current; second, it

is very difficult to cast large pieces from this impure material. This may be proved by the following: The best magnetic iron ore of Grangesberg, in Sweden, contains 91.01 per cent.' of Fe3O4, 1.04 per cent. of SlOz, 2.10 per cent. of CaO, 4.75 per cent. of P205; total, 98. 90 per cent. (the residue comprising traces of the oxids of manganese, lead, aluminium, and-magnesia.) This magnetic iron ore was melted in an electric furnace and cast in molds. It was found that it was most difficult to produce large electrodes, such as are required for technical operations, since most of the cast electrodes broke up into pieces on cooling down. ductivity of various cast pieces it was found that a cube with a face of one square centi- On testing the electrical conmeter presented a resistance of .1996 ohm.

good electrical conductivity and great resistance against chemical actions.

I have found that the product formed in the manner hereinafter described from ordinary oxid of iron is most suitable as an electrode, so that the rare, expensive, and unsuit- .in the necessary purity at an exceedingly low prlce.

In the accompanying drawing is illustrated, partly in section, an apparatus whereby the process may be carried out.

In the drawing, (0 represents an electrodecarrier adapted to be connected with the negative pole of a source of electrical current and carrying a movable electrode (Z, which is preferably of carbon.

5 represents a furnace the bottom of which is connected with the positive pole of a source of electrical current.

0 represents the channel through which the molten mass flows, and 0 represents a mold into which the molten mass flows and in which it is cooled and cast or formed into proper shape.

The electrodes produced in the described method are particularly suitable for the electrolysis of chlorids of alkalies and present the following advantages over the hithertoused anodes of carbon and platina: first, they are considerably cheaper, their price being about but a iifth of that of the carbon anodes, and they have an unlimited life in comparison With the latter; second, they furnish the chlorin free of carbonic acid, which is ol great value for the manufacture of bleaching-powder, for the volatilization ol the chlorin, and for other uses of the chlorin, and, third, they require a considerably lower tension of the current than the electrodes of platina.

In contradistinction to the electrodes prod need in the method according to the German Patent No. 92,612 the new electrodes present besides their cheapness the advantages that their conductivity is larger, that their manufacture is rendered easier by reason of their being cast with greater facility, and that they FRANZ H AssLAoi I an, MICHAEL POLK. 

